Surface contacting electrode assembly having electrically conductive pile forming contact surface



United States Patent Winston A. Love 1 18 Maple Street, Marietta, Ohio 45750 21 App]. No. 800,469

[22] Filed Feb. 19, 1969 [45] Patented Nov. 24, 1970 [72] Inventor [54] SURFACE CONTACTING ELECTRODE ASSEMBLY HAVING ELECTRICALLY CONDUCTIVE PILE FORMING CONTACT Primary Examiner-William E. Kamm AttorneyMahoney, Miller & Rambo ABSTRACT: An electrode assembly is provided for medical diagnostic work with the assembly having improved electrical contact-forming capability thereby effecting a minimal skin contact resistance. The electrode assembly is formed of electrically conductive, matted-loop pile carried on a surface of an elongated, flexible fabric strip of a length to encircle a body member for positioning of the pile in electrical contact-forming engagement with the skin surface. A multiplicity of hooks formed on an opposite surface of the fabric strip and releasably engageable with the loop pile form fastening means when interengaged to facilitate securance of the assembly to a body member. A connector terminal secured to the fabric strip and in electrical contact with the pile facilitates connection of the electrode assembly with associated diagnostic apparatus.

,Illllll till lb Patented Nov. 24;, 1970 3,542,010

INVENTOR. WINSTON A. LOVE BY. MAHONEY, MILLER 8 RAMBO BY /M ATTORNEYS S RFACE CONTACTING ELECTRODE ASSEMBLY HAVING ELECTRICALLY connncrrvn riLE FORMING conrxcr SURFACE Electronic diagnostic apparatus is widely utilized by medi cal practitioners and laboratories with this apparatus in variably requiring means for effecting electrical contact with the skin surface. Surface-contacting electrodes must be provided for such apparatus as this is the only practical means for effecting the necessary electrically conductive interconnection. With known prior art apparatus, these electrodes generally comprise structurally rigid, electrically conductive plates which are secured to the body or body member by flexible straps with appropriate fastening means. Rigid structures are not capable of conforming to the irregular and yielding body surfaces and, therefore, are incapable of making good electrical contact with consequent poor response in the connected apparatus due to the often relatively high contact re-.

not capable of conforming'to'the yieldable body surfaces and 'the contact resistance is still subject to variance as a consequence of inadvertent body movement. In addition to these structural and electrical disadvantages, the electrode jelly is inconvenient to utilize.

The electrode assemblies of this invention are capableof greatly improved response in that the contact-forming electrodes are carried by a flexible member and are resiliently flexible themselves. This flexibility provides the surface conforming capability necessary to assure good electrical contact with minimal contact resistance and high degree of reliability. Reduction of contact resistance is further enhanced by the the fabric strip is a matted-loop pile 16 which, in this embodiment, covers one entire surface of the fabric-strip. This pile 16 is formed from a resilient, fibrous material and which is electrically conductive. Normally, the pile 16 is fabricated from a nonconducting material which is made electrically conductive through impregnation or coating with a conductive material'by a suitable process. The conductive pile 16 thus forms a contact surface having a multitude of electrodes with the surface readily conformable to" the irregular, nonplanar skin surface of a body member. Combined with the flexibility of the fabric strip 15, the multiplicity of electrodes provides greater contact-forming capability than can'be achieved with the prior art rigid electrode structures. Although the mattedloop pile 16 forms alayer which is electrically conductive throughout its extent due to interconnecting engagement of the individual loops, the fabric strip 15 is also preferably made electrically conducting to enhance conduction throughout the assembly and to an electrical connecter terminal 17. The fabric strip 15 may be made conductive if not formed from an electrically conducting material in the same manner as the pile. 16.

' A fabric strip 15 with interwoven matted-loop pile 16 of the described construction and suitable for fabrication of elecmultiplicity of individual electrode elements formed by the resilient, loop-form pile. A further advantage of the electrode assemblies of this invention is that the requirement for electrode jelly is eliminated thus enhancing their convenience of use. 1

These and other objects and advantages oftheelectrode assemblies of this invention will be readily apparent from the fol- In the drawing: I

FIG. 1 is a perspective view of two electrodeassemblies embodying this invention which are particularly designed as finger electrodes and illustrates interconnection thereof with associated apparatus.

FIG. 2 is a top plan view of one of the electrode assemblies of FIG. 1 extended in a flat plane.

' lowing detailed description of an embodiment thereof and the accompanying drawing. 0

FIG. 3 is a fragmentary sectional view on an enlarged scale taken along line-3 31of FIG. 2.

Having reference to the drawing, two electrode assemblies 10 of the same construction and embodying this invention are.

shown in FIG. 1 in an illustrative application. Each electrode assembly is configured as disposed about and secured in electrical contact with the skin surface of respective fingers A and B of a hand shown in broken lines. Electrical conductors l1 and 12 connected to the respective electrode assemblies 10 facilitate interconnection with a diagnostic instrument 13 shown in FIG. 1 is exemplary as is the illustrative application which may be that utilized for determination of galvanic skinresistance.

FIGS. 2 and 3 illustrate specific structural details of this embodiment of an electrode assembly which includes, as the base element, an elongated, flexible fabric strip 15 formed from a woven material and of a configuration to encircle a particular body member such as the illustrative finger. Interwoven with trode assemblies of this invention is commerciallyavailable under the registered trademark VELCRO. In one form of the commercially available material, the fabric strip is woven of nylon and the pile is formed from nylon with the complete structure impregnated with silver by a vacuum deposition process. g

An electrical connecter-terminal 17 is secured to the fabric strip 15 and pile 16 to facilitate interconnection of theelectrode assembly 10 with the diagnostic instrument 13. This ter-' minal is preferably of a type which is readily engageable with or disengageable from a cooperative connecter 18 attached to a respective interconnecting conductor 11 or 12 to permit removal of the conductors from the electrode assemblies as is necessary when subjecting the electrode assemblies to a sterilization process. In this embodiment, the connecter terminal 17 and connecter comprise snap fastener set 'of well known form with the one .member extending through the fabric strip 15 and the pile 16 and securing the two in clamping relationship and is thus in electrical contact with both the pile and the fabric strip. The illustrated terminal 17 is of the form having a separate clamp 19 of annular ring configuration with a number of prongs (not shown) which extend through the fabric and are crimped into the base element of the terminal. The clamp plate-19'is positioned adjacent the pile 16 and is in electrical contact therewith. The annular ring configuration of the plate '19 reduces the amount of pile 16 which is crushed and rendered ineffective-A central post20 of the terminal 17 projects outwardly from the fabric strip at a surface opposite to the pile and is thus engageable with the connecter 18.

The illustrated embodiment of the electrode assembly 10 is designed to encircle a' body member such as a finger and thus comprises an elongated fabric strip 15 and pile 16 of relatively narrow, rectangular configuration as can be best seen in FIG;

2. The fabric strip 15 is of a length substantially greater than .member 21 are several uniformly spaced rows of individual 7 hooks 22 with a multiplicity of hooks in each row. Each book 22 which is formed from a single, relatively stiff although flexible strand of material is of a substa'ntiallyclosed loop configuration with the base thereof secured to a woven fabric backing member 23. The strands forming the hooks are discontinuous near the outer loop as at 24 to admit one or more of the closed loops of the pile 16. The hook member 21 is also commercially available under the trademark *VELCRO" and is utilized as it forms a convenient fastening means with the pile l6 and provides a means'of adjusting the length of the electrodeassembly for readily accommodating various sized body members. A suitable adhesive 25 may be utilized to secure the hook member 21 to the fabric strip 15.

In the utilization of this particular embodiment of the electrode assembly, the fabric strip 15 with pile 16 is wound around the finger with the pile adjacent the skin and the marginal end portions overlapped as is clearly shown in FIG. 1. The marginal end portion opposite that having the hook member secured thereto is positioned to overlie the hook member and, when the overlapped portions are pressed together, the pile 16 will interengage with the hooks 22 for the purpose of fastening the two ends together. With the conductors 11 and 12 previously secured to their respective electrode assemblies through interengagement of the connecter 18 with the terminal 17, the electrode assemblies may be connected in circuit with a particular diagnostic instrument. The

pile 16 provides a multitude of points of contact with the skin surface and thereby effects a relatively low contact resistance per unit electrode surface area for improved and more reliable results than can be obtained with the prior art apparatus comprising the structurally rigid electrodes.

While the illustrated embodiment of an electrode assembly of this invention is particularly designed for specific application to a finger, it will be apparent that the structure may be modified for other specific applications while retaining the disclosed advantages. For example, the length of the fabric strip and pile may be varied, to accommodate any particular body member; other means may be provided to secure the electrode assembly to a body surface where it is not practicable to fully encircle the member. Also, the pile 16 may be applied to only a portion of the fabric strip 15 where only a small area of contact is desired. in each instance, the flexibility of the fabric strip 15 and the matted-loop pile 16 cooperate to form an electrode assembly having a contact surface with is readily conformable to an irregular surface and which has a relatively low contact resistance thus providing substantial advantage over the structurally rigid prior art apparatus.

I claim:

I. An electrode assembly comprising an elongated, flexible fabric strip'adapted to conform to a body surface and having a matted-loop pile formed on one surface thereof, said pile formed from a resilient, fibrous material, and electrically conductive material on said pile thus forming an electrode surface comprising a multiplicity of electrodes for contact with an adjacently disposed body surface, and electric circuit interconnecting means carried by said fabric strip in electrical contact with said pile.

2. An electrode assembly according to claim 1 wherein said flexible fabric strip includes electrically conductive material.

3. An electrode assembly according to claim 1 wherein said circuit interconnecting means includes an electrical connecter terminal adapted to engage a cooperative connecter, said terminal secured to said fabric strip and engageable with a connecter at the opposite surface.

4. An electrode assembly according to claim 3 wherein said fabric strip includes electrically conductive material.

5. An electrode assembly according to claim ll wherein said fabric strip is provided with a multiplicity of hooks releasably interengageable with said pile when pressed into contacting engagement therewith, said hooks being formed on a surface of said fabric strip opposite said one surface to engage said pile when said strip is formed into a closed loop with said pile carrying surface facing inwardly and said strip overlapping at respective end portions.

6. An electrode assembly according to claim 5 wherein said pile is-formed on all of said one surface and said hooks are formed on a marginalend portion of said strip.

7. An electrode assembly according to claim 6 wherein said circuit interconnecting means includes an electrical connecter terminal secured to said fabric strip remotely to said marginal end portion. 

